EditorialPubMed ID (PMID): 36125803Pages 243-244, Language: English, GermanBeuer, Florian
ScienceDOI: 10.3290/j.ijcd.b2599735, PubMed ID (PMID): 35072419Pages 249-256, Language: English, GermanFotopoulos, Ioannis / Lillis, Theodoros / Panagiotidou, Eliza / Kapagiannidis, Ioannis / Nazaroglou, Ioannis / Dabarakis, Nikolaos
Aim: The purpose of the present study was to report early surgical template-related and postoperative complications of computer-guided implant placement and to evaluate its accuracy.
Materials and methods: Data were collected retrospectively from records of patients who had undergone computer-guided implant surgery between 2016 and 2018. Incidence of early surgical template-related and postoperative complications was recorded. Accuracy of implant placement was evaluated by comparing the data from postoperative CBCT records with that from the preoperative virtual implant planning by using appropriate image registration software. Depth, coronal, apical, and angular deviations were measured.
Results: A final number of 27 partially edentulous patients who received 52 implants with 31 static surgical templates were included in the study. All implants had been inserted in a fully guided manner using a flapless technique and following a one-stage approach. All implants were reported to have been successfully osseointegrated. Except for one template fracture, no other complication was recorded. The mean depth deviation was 0.57 ± 0.4 mm (95% CI 0.48 to 0.71 mm), the mean coronal deviation was 0.89 ± 0.7 mm (95% CI 0.73 to 1.07 mm), the mean apical deviation was 1.4 ± 1 mm (95% CI 1.16 to 1.71 mm), and the mean angular deviation was 2.74 ± 1.8 degrees (95% CI 2.29 to 3.26 degrees).
Conclusion: The use of static surgical templates for fully guided implant placement demonstrated acceptable clinical performance. However, there are some factors affecting accuracy that should be considered during implant planning and surgery for further improvement of the technique. (Int J Comput Dent 2022;25(3):249–256; doi: 10.3290/j.ijcd.b2599735)
Keywords: dental implant, guided surgery, accuracy, implant studio, 3Shape, MGUIDE, 3D printing
ScienceDOI: 10.3290/j.ijcd.b2599691, PubMed ID (PMID): 35072421Pages 257-265, Language: English, GermanYou, Ran / Han, Fei / Sun, Zhida / Xie, Haifeng / Chen, Chen
Aim: The present study aimed to determine the impact of different degrees of salivary contamination and variations in occlusal force during intraoral scanning of inlay/onlay cavities on the accuracy of fine structure reconstruction and occlusal records.
Materials and methods: Digital data of inlay/onlay models, collected using an intraoral scanner, were divided into 40 groups according to the restoration type (onlay or inlay), salivary contamination level (none, completely dry; mild, moist but not visually completely apparent; moderate, half-filled cavity; severe, filled-up cavity), and simulated occlusal force (0, 2, 4, 6 or 8 kg). The acquired 120 datasets were used to measure the average interocclusal space and cavity buccolingual internal angle.
Results: Salivary contamination and occlusal force did affect the occlusal contact (P < 0.001), but restoration type did not (P > 0.05). An interaction was found between inlay type and salivary contamination (P < 0.001), but not between occlusal force and salivary contamination (P > 0.05). Salivary contamination also affected the accuracy of fine structure reconstruction (P < 0.001), but restoration type did not (P > 0.05), and no interaction was found between the two factors (P > 0.05). The difference in the measured internal angle increased with the increase in salivary contamination.
Conclusions: Intraoral optical scanning of inlay/onlay preparations was reliable for recording occlusal contact but showed uncertainty in cavity fine structure reconstruction when moderate or severe salivary contamination was present in the cavity. Nevertheless, a moist cavity surface with no visually apparent salivary contamination is acceptable. (Int J Comput Dent 2022;25(3):257–265; doi: 10.3290/j.ijcd.b2599691)
Keywords: intraoral optical scanning, digital impression, occlusal contact, occlusal force simulation, internal angle measure, CAD/CAM, three-dimensional reconstruction, salivary contamination
ScienceDOI: 10.3290/j.ijcd.b2599709, PubMed ID (PMID): 35072420Pages 267-276, Language: English, GermanRuan, Wenhao / Zheng, Ziting / Jiang, Lifang / He, Jiahui / Sun, Jieli / Yan, Wenjuan
Ziel: In der vorliegenden Studie wurden die Spannungsverteilungsmuster, die Frakturbeständigkeit und die Bruchformen endodontisch behandelter, mit verschiedenen Höckerschutzoptionen restaurierter Molaren untersucht.
Material und Methode: Es wurden dreidimensionale Modelle von mit sechs verschiedenen Höckerschutztypen restaurierten unteren ersten Molaren generiert. T1: mesiobukkale Überkuppelung, T2: Überkuppelung aller bukkalen Höcker, T3: mesiolinguale Überkuppelung, T4: Überkuppelung aller lingualen Höcker, T5: mesiobukkale und mesiolinguale Überkuppelung, T6: Überkuppelung aller Höcker. Alle Restaurationen wurden aus zirkonoxidverstärkter Lithiumsilikatkeramik hergestellt. Die Spannungen und ihre Verteilung unter axialer und schräger Belastung wurden mit der Finiten-Elemente-(FE-)Methode analysiert. Darüber hinaus wurden sechzig humane untere Molaren randomisiert sechs Gruppen zugeordnet (n = 10), um die reale Anwendung der in der FE-Analyse untersuchten sechs Höckerschutzkonfigurationen zu simulieren, und anschließend einem Bruchlastversuch unterzogen. Alle gebrochenen Proben wurden fraktografisch untersucht. Die statistische Auswertung der Ergebnisse erfolgte mittels einfaktorieller Varianzanalyse (ANOVA), Tukey-post-hoc-Test und dem exakten Fischer-Test (α = 0,05).
Ergebnisse: Die Gruppen T2 und T6 wiesen sowohl unter axialer als auch unter schräger Belastung günstigere Spannungsverteilungsmuster auf als die anderen Konfigurationen. Die Bruchlasten in den Gruppen T2 (1.627 ± 358 N) und T6 (1.639 ± 355 N) waren signifikant höher als in den anderen Gruppen (p < 0,05). Außerdem traten in den Gruppen T2 und T6 besser restaurierbare Bruchformen auf. Fraktografisch fanden sich in den Gruppen T3, T4 und T5 mehr Bruchflächen apikal der Schmelz-Zement-Grenze.
Schlussfolgerung: Onlay-Restaurationen mit Höckerschutz aller Arbeitshöcker führten auf wurzelbehandelten Molaren zu ähnlichen Ergebnissen, wie solche mit Überkuppelung sämtlicher Höcker. Beide Höckerschutz-Konfigurationen lieferten eine gleichmäßigere Spannungsverteilung, höhere Frakturbeständigkeit und günstigere Bruchformen unter hoher okklusaler Belastung als andere Höckerschutztypen.
Keywords: Höckerschutz, Onlay, Endokrone, Wurzelkanalbehandlung, Finite-Elemente-Analyse, CAD/CAM
ScienceDOI: 10.3290/j.ijcd.b2588153, PubMed ID (PMID): 35060370Pages 277-285, Language: English, GermanMoslemian, Naeime / Koulivand, Soudabeh / Zeighami, Somayeh / Nankali, Ali / Alikhasi, Marzieh
Aim: The present study aimed to evaluate the effect of the milling mode and margin defining method on the marginal and internal adaptation of digitally designed and fabricated ceramic veneers.
Materials and methods: Forty extracted central incisors were prepared for ceramic veneers. The veneers were categorized into four groups (n = 10) based on the milling mode (fine or extra-fine) and design (automatic or manual defining of cervical and incisal margins). The veneers were cemented to the teeth using resin cement and then polished. After cementation, the teeth were embedded in clear polyester resin, then cut into three sections. Absolute marginal gap at the cervical margins (AMGC), marginal gap at the incisal (MGI) and cervical (MGC) margins, and internal gap (IG) at the axial wall were evaluated using a scanning electron microscope. Two-way analysis of variance (ANOVA) and t tests were used (α = 0.05) for the statistical analysis.
Results: The margin defining method affected the adaptation of the internal and incisal margin; the automatic (software) margin defining method resulted in a smaller MGI (P = 0.038) and IG (P = 0.009) than the manual defining method.
Conclusion: The type of milling mode did not affect the marginal gap. The margin defining method affected the marginal gap at the incisal margin and the internal gaps. (Int J Comput Dent 2022;25(3):277–285; doi: 10.3290/j.ijcd.b2588153)
Keywords: veneer, margin defining, SEM, CAD/CAM, marginal adaptation, ceramic
ScienceDOI: 10.3290/j.ijcd.b2599661, PubMed ID (PMID): 35072422Pages 287-294, Language: English, GermanZou, Yun / Zhan, DeSong / Xiang, JingZhou / Li, Ly
Objective: To assess the clinical status of monolithic zirconia CAD/CAM endocrowns and crowns on post and core buildups in endodontically treated molars after 5 years of clinical service.
Materials and methods: A total of 670 patients who received restorations for excessive defects at Ansteel Group Hospital from 2012 to 2015 were selected and randomly divided into two groups: 334 patients in the endocrown group and 336 in the post and core crown group. All the treatments were performed using a digital CAD/CAM system. The prostheses restorations at 1, 3, and 5 years after treatment were evaluated using the USPHS (United States Public Health Service) criteria and satisfaction questionnaire. In addition, the time cost of tooth preparation was recorded by the clinicians.
Results: Most of the patients in both groups reported grade A at the after-treatment follow-ups. Gingival health, food impaction, marginal accuracy, and general satisfaction at 3 and 5 years after treatment in the endocrown group rated higher (P < 0.05) than in the post and core crown group. There was no statistical difference in other indicators between the two groups at all observational after-treatment timepoints (P > 0.05). The time cost of tooth preparation in the post and core crown group was significantly higher than that in the endocrown group.
Conclusion: A CAD/CAM scanning system combined with a monolithic zirconia endocrown restoration was rated very positively by the participants. Endocrown restorations are a significantly superior choice compared with post and core crowns in clinical application. (Int J Comput Dent 2022;25(3):287–294; doi: 10.3290/j.ijcd.b2599661)
Keywords: monolithic zirconia endocrowns, crowns on post and core buildups, CAD/CAM fabrication
ScienceDOI: 10.3290/j.ijcd.b2599775, PubMed ID (PMID): 35072417Pages 295-302, Language: English, GermanKoch, Petra Julia / Albrecht, Marco / Lin, Wei-Cheng / Jost-Brinkmann, Paul-Georg
Aim: To present an image-processing measurement algorithm to evaluate the transfer accuracy of indirect bonding (IDB) trays, exemplified by a CAD/CAM-based IDB tray integrated into a digital orthodontic workflow.
Materials and methods: Plaster casts of 24 patients with full dentition and different malocclusions were scanned with an intraoral scanner (Trios; 3Shape, Copenhagen, Denmark) to obtain digital models, which served for the virtual placement of orthodontic brackets in simulation software (OnyxCeph; Image Instruments, Chemnitz, Germany). The resulting STL files were sent to a dental laboratory (CA Digital; Hilden, Germany) for the production of INDIVIDUA IDB trays. These trays were used to transfer the brackets to the respective plaster casts. Finally, a second scan was performed to record the actual bracket positions. The transfer accuracy was then analyzed by a measurement algorithm scripted to automation, which calculated the deviations of the planned and real bracket positions with a local best-fit alignment, resulting in three linear and three angular measurements for each bracket.
Results: In total, 622 brackets and tubes were transferred successfully. The presented algorithm analyzed the transfer accuracy and demonstrated that the linear measurements were 98.3% within the range of the American Board of Orthodontics standard. The angular measurements were 86.7% within this range when the INDIVIDUA IDB tray was used.
Conclusion: Scripted measurement algorithms facilitated the evaluation of present and future materials and designs for IDB trays to obtain an efficient solution for orthodontic practice. The INDIVIDUA IDB tray is a digital alternative to conventional IDB trays (Int J Comput Dent 2022;25(3):295–302; doi: 10.3290/j.ijcd.b2599775).
Keywords: digital workflow, indirect bonding tray, transfer accuracy, digital orthodontics, 3D superimposition, 3D automation, best-fit alignment, intraoral scan, measurement algorithm
ApplicationDOI: 10.3290/j.ijcd.b3380919, PubMed ID (PMID): 36125804Pages 303-323, Language: English, GermanNorré, David / Att, Wael
The digital workflow in implant dentistry aims to provide safer and predictable implant placement. This is facilitated through visualization of the anatomical structures as well as the integration of the prosthetic information to dictate implant placement. Guided surgery is useful in edentulous arches planned for fixed rehabilitations, where the unfavorable position of the implants may limit the possibility to realize such a treatment option. In full-arch immediate implant placement and immediate loading, computer-guided implant surgery gains a significant importance. Here, clinicians rely on either soft tissue or bone to provide support for the surgical guide during implant placement. Due to tooth extraction and the loss of anatomical structures that improve the support of the surgical guide, the correct positioning of the guide can be challenging. Further, the procedure that follows to deliver the immediate temporary rehabilitation can also be challenging due to the lack of workflow integrity between the surgical and restorative phases. The present case report describes a novel digital workflow for immediate implant placement and immediate loading of a full-arch rehabilitation, which aims to improve the accuracy of implant placement surgery and simplify the procedure of delivering immediate provisional restorations. (Int J Comput Dent 2022;25(3):303–323; doi: 10.3290/j.ijcd.b3380919)
Keywords: immediate loading, guided implant placement, virtual planning, surgical guide, prosthetic guide, digital implantology
ApplicationDOI: 10.3290/j.ijcd.b3380909, PubMed ID (PMID): 36125805Pages 325-332, Language: English, GermanHöhne, Christian / Schmitter, Marc
Ziel: Mit der Entwicklung neuer Materialien hat der 3-D-Druck enorme Auswirkungen auf die Zahnmedizin. Die neuesten Innovationen sind die direkte Herstellung von temporären und permanenten Kronen- und Brückenrestaurationen, Inlays, Onlays und Veneers. In diesem Fallbericht wurde die 3-D-Drucktechnologie verwendet, um die okklusale Rehabilitation mit 3-D-gedruckten Kronen zu kontrollieren und anzupassen.
Material und Methoden: Ein 44-jähriger Mann mit pathologischer Attrition stellte sich in der Poliklinik für restaurative Zahnheilkunde der Universität Würzburg vor. Der Prozess war weit fortgeschritten und es war keine konventionelle konservative Therapie mehr möglich. Für die Rehabilitation des Substanzverlustes, der Zahnhöhe und des Aussehens wurde eine dauerhafte Lösung mit Zahnkronen gewählt. Nach der Präparation wurden die Restaurationen digital konstruiert. Zur Kontrolle der okklusalen Höhe, des Aussehens und der Farbe wurden die Kronen mit einem 3-D-Drucker hergestellt und provisorisch zementiert. Die Kronen hatten eine hohe Präzision und es waren nur minimale okklusale Korrekturen erforderlich. Nach einer Probezeit von 2 Wochen und einer weiteren okklusalen Feineinstellung wurden die provisorischen Kronen entfernt und gescannt. Die Daten wurden mit der ursprünglichen Konstruktionsdatei abgeglichen und können verwendet werden, um die definite Restauration zu optimieren. Die endgültigen Restaurationen bestanden aus Kronen, die aus monolithischem Zirkonoxid gefertigt wurden. Es waren nur minimale okklusale Korrekturen erforderlich.
Fazit: Die Zahnmedizin erlebt derzeit großen Veränderungen durch neue und zukunftsweisende Produktionstechnologien im Bereich des 3-D-Drucks. Dadurch erhalten Zahnärzt/-innen die Möglichkeit, vorhersehbarere und kostengünstigere Behandlungen durchzuführen. Der 3-D-Druck kann bereits jetzt für die Herstellung von temporären und endgültigen Zahnkronen und komplexen Behandlungen verwendet werden, wie in diesem Fallbericht dargestellt.
Keywords: digitale Zahnmedizin, 3-D-Druck, Stereolithographie, additive Fertigung, Rapid Prototyping, CAD/CAM, provisorische Kronen, keramische Restaurationen, zahnärztliche Prothetik